Dual anode



Sept. 25, 1934. o. v. STEWART r-:r AL

QUAL ANQDE originar Filed 1mg'.v 13, 192'? ATTORNEY 'active and inactive elements was desirable but. 20

Reixsued Sept. 25, 1934 PATENT; ori-icav naar. Nona -otno v. stewmand Emu Urban, Forest mns, Pa., assignors to Westinghouse Electric and Manufacturing Company,

Pennsylvania a corporation of Original No.`1,765,'l06, dated June 24, 1930, Serial No. 212,652, August 13,1927. Application for reissue March'5, 1932, Serial No. 591,044

19 Claims.

Our invention relates to the process of'electroplating and has particular reference to a dual or two-element anode in which one or both of the elements may be readily replaced.

Heretofore it was known that when a soluble anode was used that the metal of the anode would Aoperate to replenish the electro-plating material in the bath but that rapid dissolution of the anode sometimes resulted in polarization, thus eventually slowing down or preventing the replenishment of the bath. It was found when the anode was made of two metals, one an active metal which was being consumed in the electro-plating process and the other an inactive metal such as carbon, iron or steel which was not consumed,

that polarization of the active 'element was prac-- tically eliminated.

It was found that a certain ratio between the the structures utilized were found to possess several mechanical dimculties. that the active material w'as consumed while the inactive material was not, and that, as the result thereofthe ratio of exposed area of inactive anode surface to the exposed area of active anode surface was changed materially during the process and partially consumed anodes had to be replaced with n'ew ones in order to preserve the ratio.

The active material was fastened to the inactive material by mechanical devices and corrosion of the devices made removal of the active material Adiilicult. 'I'hus the operation of changing the active material of the anode involveda considerable loss of time and destruction of the insoluble anode. Therefore, it is one Aof the objects of our invention to provide an anode for electroplating in which the plating metal may be readily replenished as it is consumed.

Another object of our invention is to provide a two element anode in which the desired ratio between active and inactive material may be continuously maintained as the active material is consumed. f

Another object of our invention is to provide a dual anode in which the active element may be entirely consumed after 'having been once placed in the plating bath. y

A still further object of our invention is to provide an anode which, by reason of its construction, readily lends itself to a computation o! the weight of plating metal consumed over any given period of time. f

Our invention may be more readily understood by reference to the accompanying4 drawing in which like figures' indicate like parts.

One difficulty was Figure 1 is a sectional end view of an electroplating bath having ouranode mounted therein;

Fig. 2 is a top view of the anode;

- Fig. 3 is an end view of the anode shown in Fig. 2;

Fig. 4 is a modified form of our anode adapted to be suspended vertically from a bus bar. Referring more particularly to Fig. 1, in which a device for cadmium plating is shown, the material 1 to be-'plated is placed in a plating drum 2 and the plating drum is partially submerged in theplating bath 3 in the containen 4. Copper rods 5' longitudinally disposed with relation to the container provide a support for the anode 6 and are connected to the positive side of a power line. The sides 7 of the plating drum may be constructed of a non-metallic material such as wood. Electrical connection to the negative side ofa power line may be made through the axle 8 of the' plating drum. The ring 9 engages the axle and carries other rings l0 .whchvare allowed to come into contact with the material to be plated, thus forming the cathode.

The plating drum may be a six-sided barrelshaped member and may be slowly rotated so that the material to be plated will be tumbled and all sides of the material will'receive a uniform coating. v

The anode 6 is a tubular member 14 provided with a suspending hook portion 15 at each end which may be secured to the tubular member` by any suitable means, such as a Weld, as indicated at 14 in the drawing. The cadmium or active elementis preferably in the form of rods or balls 16 of such dimensions that they can be readily inserted in the tubular portion 14 of the anode. A slot 17 is provided in the tubular member in order to permit the circulation of the electrolyte around the active anode material. The ratio of active to inactive material may be controlled by lvarying the'size of the slot.4 vIf desired, a, plurality of openings such as those shown in Fig. 4 may be substituted for the slot 17.

As impurities are present in the cadmium and other impurities collect in the bottom portion of thek anode, a discharge slot 18 is provided in the under side of the anode in order that these impurities may be dislodged and discharged.

As the cadmium is consumed, the balls inthe upper portion of the anode drop downwardly,

thus leaving space for inserting new active material. In practice, the proportions of active material, as represented by cadmium balls, and the inactive material, as represented by the tubular container may be conveniently proportioned so that the correct ratio of active to inactive material will exist `when active metal projects above the surface of the electrolyte. When the balls disappear belowthe surface of the plating bath,

new balls may be added in order to maintain the inactive element of the anode is comprised of a tubular member 20 closed at the bottom and provided with a number of openings 19 at its side. The tubular member is suspendedfrom the positive bus bar 21 by means of a hook 22 which is secured to the tubular member 20 by any suitable means, such as a weld, as indicated at 18. 'I'he cadmium balls 16 are placed inside of the container, as before, andthe consumption of cadmium @progresses during the electrolysis. The solution may pass into the container through the openings in the side thereof and dissolve the cadmium'. 'Ihe ratio of active to inactive material may be controlled by varying the size yand numof the openings. A plating metal, such as cadmium, may be readily replenished without loss i' of time as it is consumed. The entire active element is consumed without removing it from the electro-plating bath and the amount of plating material consumed during a predetermined period may bereadily computed. Y

From this description and the accompanying drawing. it is' apparent that this invention provides a composite anode for electro-plating, having in combination -a housing of elongate structure vvariable to control the ratio of active anode surface by wall openings vpermittinaLi'ree ow vof electrolyte and oi material that is insoluble in theelectrolyte, suchasferrousmetalforexample, containing Va. consumable, self anode of relatively soluble plating metal, such as for example, in the form ora single column of approximately spheroidal units, to

substantially constant surface condiof the anode during Although we'have describedaspectc modicatimiofadevicemrrinvmtionwith refauice to the electrode of cadmium, weanotwishtobelimitedthsetonsthedev'ice mylieutilizedinvarloprocmanhasnickelplaidng'andplatiig.r lodiilcationsn the fam of tlm hllmlar mandothermodiilcaimsmaybemawith- .mtlnrtingiromthesliritlndm Glourinmudeilnedintheappmedchm 'c daimasourinvmm: Lnanodeatlllmlarrecemdbody dixnetlvematerialforapluralityof bodisol active materialandpmvid with an Ymailxateachend.timeaxisolsaidbodybetng semi-umularmiomandmeansonsail-body foanelectricaleltact.-

2.Anannclecomprising.. Y- bodyotinmuseum-inforum othnlbdadivematerisaidremedbody bdlg'mi-umularandtubulanandmeanson weaclrmdtlnredtorsaidbody.

3. Ananodcarecndhodyd'mactive anode material for supporting-a plurality of bodies of active material, said recessed body bei118 semi-annular Aand tubular and means on each Iend i'or supporting said body, said body being slotted to permit contact of the electrolyte with the active material. v

4. An anode comprising active and inactive material said inactive material including a tubular recessed body for supporting a plurality of bodies of active material, said recessed body having a slot in its normally upper portion to permit contact of the electrolyte with said active material and another slot in its normally lower portion to permit the discharge' of impurities, and supporting means at each endv of said tubular body.

v5. An anode comprising active and inactive material, said inactive material including' a recessed body for supporting a plurality of bodies of the active material, said recessed body being in the form of a semi-annular tube having a plurality of open'- ings to permit contact of the'electrolyte with the active material, and supporting means at each end of said tubular body.

6. An anode comprising active and inactive material, said inactive material. including a tubular recessed body, said recessed body having an opening for' inserting active material and another opening for providing contact of electrolyte with the active material and a hook on said inactive material for supporting the same. '195 7. An anode comprising a recessed tubular member of inactive material for supporting a plurality or bodies oi active material, said tubular member being provided with an opening at each end for inserting the active material and with an elongated slot for permitting an electrolyte to uniformly come in contact with all portions of the active material. i i 8. An anode comprising a recessed tubular member of inactive material for supporting a plurality of bodies of active material, said .tubular member being provided with an opening at each end for insertion of the active material and with f a slot extending throughout its length to permit an electrolyte to uniformly come in contact wi all portions o'i' the active material;

9. An anode comprising a curved integraltuhular recessed body of inactive material-fior supporting a plurality of bodies of active material, said tubularbody being provided with an opening at each end for the insertion of active mate-- rial and with an elongated slot to ensure a uniform ratio between the exposed area of the lactive and that of the inactive material, and means for supporting-said anode.

1o. A two-element anode comprising a curved tubular we n body oi inactive material and a plurality of 'bodies of activematerial supported thereby, said tubular. body being provided with a l slot inits normally upper portion to provkie adenite ratio betweenthe exposed arca r of the active and that ofthe inactive material, inopening at each end for insertionof additional activematerial sothat'the ratiomaybemaintained substantially. constant, and another slot in im normally lower portion to permit the discharge of impurities. i v

11. A two-element anode comprisinga curved tubular uw bodyoifinactivematerialanldaV plurality embodies of active material simpel-ted thereby said tubular body beingprovided with 'a slotinitsnormallyupnerportionto vprovide adeiinite ratio between the area oi the active and thatof the inactive material `'andanopening ateachendforinsertionof addi- *50 I mass tional active material, and means for supporting said anode.

12. A composite anode for electro-deposition.

comprising in combination a housing of elongate.

open-wall structure permitting free flow of electrolyte therethrough and relatively insoluble in the electrolyte, containing a consumable anode or relatively soluble plating metal in the i'orm of a single column of approximately spheroidal umts, to maintain substantially constant surface conditions oi' the anode during electro-plating.

13. A composite anode for electro-deposition,

' comprising in combination an electrically conducting housing of elongate, open-wall structure permitting i'ree ilow oi' electrolyte therethrough and relatively soluble in the electrolyte, containing a consumable anode of relatively soluble plating metal in the iorm of a single column of approximately spheroidal umts, to maintain substantially constant surface conditions of the.

anode during electro-plating.

14. A composite anode for electro-deposition, comprising in combination a housing of elongate, open-wall structure permitting i'ree flow oi' electrolyte therethrough and relatively insoluble in the electrolyte, containing a consumable anode of cadmium as relatively soluble plating metal in the form oi a single column of approximately` to maintain substantially constant surface conditions of the anode during electro-plating, `said umts being in electrical contact with the ferrous metal. v

16. A composite anode for use in electro-de osition, comprising a relatively long and narrow hollow cage oi' foraminous, material, relatively insoluble in the electrolyte and conductive of electric current. and a plurality oi' selfdescending soluble anode balls of metal to be deposited, said self-descending balls being relatively large so as substantially to illl the crosssection of the cage, and said cage being replenishable with anode balls on solution of the metal to be deposited. y

17. A soluble electro-plating anode comprising metal consumable in an electro-plating bath and arranged in the form of' a single-column of apn l proximately spheroidal units i'or advancement in the column as the metal is consumed.

18. A consumable electro-plating'anode comprising an elongate carrier relatively insoluble in an electro-plating bath with relatively soluble metal for electro-deposition, supported by the carrier, in the form of a plurality ot approximately spheroidal units arranged for advancement as the metal is consumed, the units in at least the more extensive portion ot soluble metal surface being aligned in a single column.

19. A consumable electro-plating anode 'com- 105 'prising a columnar; open-wall housing relatively uns 

